US3637532A - Sintered cold-conductor resistor body and method for its production - Google Patents

Sintered cold-conductor resistor body and method for its production Download PDF

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US3637532A
US3637532A US852147A US3637532DA US3637532A US 3637532 A US3637532 A US 3637532A US 852147 A US852147 A US 852147A US 3637532D A US3637532D A US 3637532DA US 3637532 A US3637532 A US 3637532A
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barium titanate
curie temperature
phase
resistor
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Emil Ramisch
Werner Schwan
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Siemens AG
Siemens Corp
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Siemens Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H01C7/022—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient mainly consisting of non-metallic substances
    • H01C7/023—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient mainly consisting of non-metallic substances containing oxides or oxidic compounds, e.g. ferrites
    • H01C7/025—Perovskites, e.g. titanates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
    • C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
    • C04B35/465—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates
    • C04B35/468—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on barium titanates
    • C04B35/4682—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on barium titanates based on BaTiO3 perovskite phase
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
    • H01B1/08—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient

Definitions

  • the invention relates to a sintered electrical resistor body of ceramic material having a high positive temperature coeffieient of resistance (FTC-resistor).
  • the ceramic material consists of a doped ferroelectric substance having aperowskite structure, such as,-for example, barium titanate doped with antimony for the production of N-conductivity. Also other known substances having perowskite structures and other known doping agents are suitable as materials for ceramic PTC-resistors.
  • these materials have perowskite structures which are constituted essentially on the basis of barium titanate and present in the form of mixed crystals which corresponds to the general formula in which Me" is chiefly one or several alkaline earth metals and/or lead and Me is preferably one or more tetravalent metals, such as, for example, titanium, tin and/or Zirconium. Me" and Me are so-called perowskite structure-forming elements.
  • the doping substances in themselves are not perowskite structure-forming substances, but are present in certain small amounts on Me"--and/or Me"'-places in the perowskite lattice.
  • doping substances differs from II and IV, so that through the doping, N- or P-conductivity of the material results.
  • doping substances ac.- cordingly, there come into consideration chiefly antimony, niobium, bismuth, tungsten and rare earth metals.
  • the materials having perowskite structure occur in various crystal modifications. Above the Curie temperature the crystal lattice is cubic, while at the Curie temperature or in the Curie temperature range it is transfonned into the ferroelectric tetragonal form and, at still lower temperatures it may pass over into the orthorhombic crystal modification. Of interest in the present case is the transformation at the Curie temperature.
  • the Curie temperature which, for example, in the case of pure barium titanate lies at about 120 C., can be shifted by additions such as strontium, zirconium or tin to lower temperatures, and by additions such as lead to higher temperatures.
  • the above-mentioned materials have, below the Curie temperature, a relatively low specific electric resistance, which lies at about 100 ohm-cm. in the vicinity of the Curie temperature the specific resistance climbs relatively sharply, as a rule by about four powers of 10, to maximum values up to ohm-cm.
  • This strong increase in theresistance takes place within a temperature range beginning approximately at the Curie temperature, with the resistance maximum being reached at temperatures which lie about 40 to l50 above the Curie temperature.
  • Ceramic resistors of the type described therefore, have in the range of the Curie temperature a strong positive change of the resistance value in dependence on the temperature. in the temperature range of the resistance maximum a strong dependence of the resistance value on the applied field strength (volt/cm.) becomes noticeable.
  • the specific resistance begins to decline severely at field strengths from the order of 10 v./cm. upward.
  • varistor effect-the load quotient B As a measure for the decline of the specific resistance with increasingly applied field strength, designated in the following as the varistor effect-the load quotient B shall here be defined as:
  • the load quotient defined in this manner for pure doped barium titanate lies about between 6 and 10 percent.
  • the values of the load quotient lie in about the same range.
  • One of the objects of the present invention is to reduce the varistor efi'ect, that is, to increase the load quotient.
  • a sintered FTC-resistor body of the type initially referred to which is characterized, according to the invention, by the feature that it consists of at least two crystalline main phases, of which one phase has a temperature range of increasing resistance which lies above, and another phase has a temperature range of increasing resistance which lies below the desired resulting temperature range of increasing resistance of the resistor body.
  • crystal granules which are alike, both in their composition and in their properties, are designated as a main phase.
  • the FTC-resistor bodies according to the invention differ, therefore from the known ceramic resistor bodies in that they contain at least two crystalline main phases, while the known bodies are essentially monophase.
  • methods of investigation for the determination of such bodies at least having a twophased structure according to the invention there are suggested, for example, X-ray structure analysis or the method of formation of etched figures, which can then be analyzed under a sufficiently high powered microscope.
  • the monophase state in the known resistance bodies results from known production processes which have in common the feature that for desired Curie temperatures differing from l20 C. both the perowskitc-forming substances and also the doping substances in oxide form, or in the form of compounds yielding oxide on heating, such as, for example, carbonates are mixed with one another in corresponding quantitative relations and such mixture is heated to temperatures, for example of l,000 C., at which the conversion reaction takes place to the perowskite material with the desired Curie temperature.
  • the desired Curie temperature is dependent on the quantitative proportions of those substances which have an increasing or decreasing effect on the Curie temperature.
  • These processes will be designated in the following as processes with common conversion of the initial components.
  • the converted material is, as a rule, ground, treated with binders and plasticizing agents, shaped to the desired bodies and then subjected to sintering at temperatures above 1,300" C.
  • the resistor bodies resulting according to these processes have the above-described drawback of the strong varistor effect.
  • FIG. 1 is a chart illustrating the course of increasing resistance of different FTC-resistor materials
  • FIG. 2 is a chart illustrating the dependence of specific resistance on applied field strengths
  • FIG. 3 is a chart illustrating the dependence of the load quo tient on the mixing ratio
  • FIG. 4 illustrates a ceramic PTC-resistor according to the invention.
  • FIG. 5 is an enlarged view of the portion C of FIG. 4, illustrating the two crystalline main phases.
  • the desired temperature range of increasing resistance of the FTC-resistor bodies according to the invention results from the position of the temperature ranges of increasing resistance and the relative amounts of the individual crystalline main phases in the body. That is, with the presence of two crystalline main phases of which the one has, for example, a Curie temperature of 120 C. and the other, for example, a Curie temperature of 40 C. and these crystalline main phases are present in the ratio of 1:1 in the resistor body, the body will have a Curie temperature of 80 C. and thereby a temperature range of increasing resistance which begins at about 80 C.
  • one crystalline main phase consists of doped barium titanate with a temperature range of increasing resistance around 120 C. and the other crystalline main phase consists of doped substituted barium titanate, the temperature range of increasing resistance of which, in consequence of the proportion of substituents known per se lowering the Curie temperature lies below 100 C., in particular, below 60 C.
  • substituents lowering the Curie temperature there are advantageously used calcium and strontium in the cation constituent and/or tin or zirconium in the anion constituent, individually or in combination.
  • the proportion of cation substituents amounts to 2 to 48 mol percent, with reference to the total molar amount of cations, and the proportion of anion substituents amounts to l to mol percent, with reference to the total molar amount of anions.
  • the one crystalline main phase to consist of doped substituted barium titanate whose temperature range of increasing resistance, in consequence of the proportion of Curie temperature increasing substituents known per se, for example lead, in amounts of l to mol percent, lies above 130 C., preferably above 170 C., and in particular at 180 C.
  • the other crystalline main phase consists of doped substituted barium titanate whose temperature range of increasing resistance, in consequence of the proportion of Curie temperature lowering substituents known per seand given above, lies below 100 C., preferably at 60 C.
  • Such a resistor body may, for example, have a Curie temperature of 120 C., such as is present in pure BaTiO but the load quotient is improved as compared to that of pure BaTiO
  • The- Curie temperature of C. can be achieved, for example, by a 1:1 mixture of a material with a Curie temperature of 60 C. anda material with a Curie temperature of 180 C. It appears that with greater separation of the Curie temperatures of the materials to be mixed, the load quotient of the mixing body is more strongly improved, as compared to the load quotient of the monophase body with equal resulting Curie temperature.
  • one crystalline main phase consists of doped barium lead titanate and the other crystalline main phase consists of doped pure barium titanate with a Curie temperature at 120 C. t
  • the desired resulting temperature range of increasing resistance lies between the ranges of the individual crystalline main phases, in which, as is apparent from FIG. 1, overlapping of the temperature ranges is possible.
  • the FTC-resistor bodies according to the invention are produced by a process which, according to the invention, is characterized in that, first of all, the formation of the individual crystalline main phases is accomplished by' the method that according to processes known per se doped ferroelectric perowskite materials of the oxides, of oxide yielding compounds such as, for example, carbonates, are individually produced, through individual mixing of the same, and converting at temperature up to about 1,100 C., following which these individually prefired perowskite materials are mixed with one another, in the amounts necessary for the desired resulting temperature range of increasing resistance, molded into bodies and sintered for about 1 hour at temperatures between l,300 and l,380 C.
  • the chart in FIG. 1 shows, as curves 1 and 2, the course of increasing resistance of PTC- resistor materials with Curie temperatures of 120 C. in curve I, and 180 C. in curve 2.
  • the material shown in curve 1 was pure barium titanate, which was doped with 0.086 mol percent Sb O
  • the material ll shown in curve 2 consisted of 84.3 mol percent BaO, 15.7 percent PbO, these molar percents being referred to the total molar amount of the cations, of 101.5 mol percent Ti0 as well as 0.086 mol percent Sb O
  • the doping substance proportion is with the reference to the total molar amount of the converted product.
  • Curve 3 illustrates the resistance increase of a two-phased FTC-resistor body composed of the two materials I and II in the ratio 1:1 in which the Curie temperature lies at C.
  • the material which was used as the basis for curve 4 was composed of the materials I and II in the ratio 1:2, with Curie temperature, accordingly, lying at C.
  • FIG. 1 there also are plotted temperature ranges of increasing resistance for the materials I and II, as well as for the 1:1 mixed body and designated as 111,
  • the chart according to H0. 2 illustrates the course of the specific resistance in dependence on the applied field strength, measured at the temperature at which the particular specific resistance has its maximum.
  • Curve 5 holds for material with a Curie temperature of 120 C.
  • curve 6 holds for material with the Curie temperature of 180 C.
  • the B-values of these materials lie about between 6 and 10 percent.
  • Curve 7 holds for a two-phase FTC-resistor body according to the invention, which has a resulting Curie temperature of 150 C. and curve 8 holds for such a body with a Curie temperature of 160 C.
  • the chart according to FIG. 3 shows the position of the load quotient in dependence on the mixing ratio.
  • abscissa direction there are plotted the percentages by weight of the main phase with a Curie temperature of 180 C. from to 100 percent by weight and running oppositely thereto are plotted the percentages by weight of the material with a Curie temperature of 120 C. Further there are presented in abscissa direction, the Curie temperatures applying to the particular mixtures,
  • the load quotients lie in the range A, while when the individual phases are converted separately from one another and the two-phase body is then prepared from the two, the load quotients lie in the range B. From this the improvement of the load quotients is apparent.
  • FIG. 4 illustrates a ceramic cold-conductor resistor according to the invention, which consists of the resistor body 10, the contact coverings l1 and 12, applied without blocking layer, and the outer connecting contacts 13 and 14.
  • FIG. represents one edge portion C cut out of the body 10 in FIG. 4, on a larger scale.
  • FIG. represents one edge portion C cut out of the body 10 in FIG. 4, on a larger scale.
  • the two crystalline main phases there are schematically represented the two crystalline main phases.
  • the crystal granules of one crystalline main phase are hatched perpendicularly to the body edge and the crystal granules of the other crystalline main phase are hatched parallel to the body edge.
  • Resistor bodies produced from materials I and 11 by plastification, molding and sintering according to known processes produced PTC-resistor bodies with the resistance increase curves 1 and 2, respectively (FIG. 1) and with the varistor effect curves 5 and 6, respectively (FIG. 2), while the load quotients lie in the range A of FIG. 3.
  • the materials 1 and 11 are mixed, for example, in the ratio of 1:1, ground, either before the mixing or during the mixing process, to granule sizes smaller than 3 microns under alcohol or, after previous separate grinding, mixed dry, the mixture is treated with plasticizing agents in themselves known (for example, 12 percent of a mixture of polyvinyl alcohol, glycerin and water), then, through pressing, shaped into the desired bodies, which bodies are sintered in an oxygen-containing atmosphere (for example, air) for 1 hour at 1,300 to l,380 C.
  • the thus resulting FTC-resistor bodies have a Curie temperature of 150 C.
  • the load quotient amounts to 20 to 30 percent.
  • bodies with a gross chemical composition which likewise yields a Curie temperature of 150 C. but which were produced by simultaneous conversion of the oxide starting components, have only a load quotient which lies between 6 and 10 percent.
  • An electrical resistor having an increase of specific resistance on the order of four powers of 10 in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of ohm-cm. and below, and having a load quotient on the order of 20 to 30 percent, said resistor consisting of a body of sintered N-type conductivity ferroelectric materials each having a perowskite structure and each having the empirical formula Me"Me"'O wherein Me” is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead and Me is at least one tetravalent metal selected from the group consisting of titanium, tin and zirconium, said body having N- type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten and rare earth metals, said body comprising two discrete crystalline phases in substantially equal amounts by weight, one of the phases consisting of I a barium titan
  • An electrical resistor having an increase of specific resistance on the order of four powers of 10 in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of 100 ohm-cm. and below, and having a load quotient on the order of 20 to 30 percent, said resistor consisting of a body of sintered N-type conductivity ferroelectric materials each having a perowskite structure and each having the empirical formula Me"Me"'O wherein Me" is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead and Me is at least one tetravalent metal selected from the group consisting of titanium, tin and zirconium, said body having N- type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten and rare earth metals, said body comprising two discrete crystalline phases in substantially equal amounts by weight, one of the phases consisting of a barium titan
  • An electrical resistor having an increase of specific resistance on the order of four powers of l in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of 100 ohm-cm. and below, and having a load quotient on the order of 20 to 30 percent, said resistor consisting of a body of sintered N-type conductivity ferroelectric materials each having a perowskite structure and each having the empirical formula Me"Me"'O wherein Me” is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead and Me is at least one tetravalent metal selected from the group consisting of titanium tin and zirconium, said body having N- type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten and rare earth metals, said body comprising two discrete crystalline phases in substantially equal amounts by weight, one of the phases consisting of a barium titan
  • An electrical resistor having an increase of specific resistance on the order of four powers of in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of 100 ohm-cm. and below, and having a load quotient on the order of 20 to 30 percent, said resistor consisting of a body of sintered N-type conductivity ferroelectric materials each having a perowskite structure and each having the empirical formula Me"Me"0 wherein Me" is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead and Me is at least one tetravalent selected from the group consisting of titanium, tin and zirconium, said body having N-type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten and rare earth metals, said body comprising two discrete crystalline phases in substantially equal amounts by weight, one of the phases consisting of a barium titanate lat
  • An electrical resistor having an increase of specific resistance on the order of four powers of 10 in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of I00 ohm-cm. and below, and having a load quotient on the order of to 30 percent, said resistor consisting of a body of sintered N-type conductivity ferroelectric materials each having a perowskite structure and each having the empirical formula Me"Me"O wherein Me" is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead and Me is at least one tetravalent metal selected from the group consisting of titanium, tin and zirconium, said body having N- type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten and rare earth metals, said body comprising two discrete crystalline phases in substantially equal amounts by weight, one of the phases consisting of a barium titanate
  • both of said phases are substituted barium titanate, one of which contains from 1 to 30 mol percent lead in substitution for the corresponding amount of barium, and the other of which contains from 2 to 48 mol percent of an element selected from the group consisting of calcium and strontium in substitution for the corresponding amount of barium, and from 1 to 15 mol percent of a metal selected from the group consisting of tin and zirconium in substitution for the corresponding amount of lead.
  • one phase has the formula BaO'l.0l(TiO containing 0.086 mol percent Sb 0 as a dopant and having a Curie temperature of 120 C. and the other phase has the formula (Ba Sr )-(Tj Sn )O containing 0.124 mol percent sb,o as a dopant and has a Curie temperature of 40 C.
  • one phase has the formula BaO-l.0l(TiO containing 0.086 mol percent Sb O as a dopant and has a Curie temperature of 120 C. and the other phase consists of doped substituted barium titanate having the formula (Ba Pb )O'l.015(TiO containing 0.086 mol percent Sb 0 as a dopant and has a Curie temperature of 1 80 C.
  • one phase is a doped substituted barium titanate having the formula (Ba Sr (Ti ,Sn )O containing 0.l24 mol percent Sb O as a dopant and having a Curie temperature of 40 C. and the other phase is a doped substituted barium titanate having the formula (Ba Pb -,)O- l .0l5(TiO containing 0.086 mol percent Sb O as a dopant and having a Curie temperature of C.
  • a method for producing an electrical resistor having an increase of specific resistance on the order of four powers of 10 in a predetermined temperature range and having a specific resistance at temperatures below said range on the order of I00 ohm-cm. and below, and having a load quotient on the order of 20 to 30 percent which comprises first forming a plurality of compositions each having the empirical formula Me"Me"'0 wherein Me" is at least one bivalent metal selected from the group consisting of the alkaline earth metals and lead, and Me is at least one tetravalent metal selected from the group consisting of titanium, tin and zirconium, each composition having N-type conductivity by virtue of the presence in the crystalline lattice of a dopant selected from the group consisting of antimony, niobium, bismuth, tungsten, and rare earth metals, the Curie temperatures of said compositions differing by at least 20 C., heating each of said compositions individually at temperatures up to l,l00 C. to produce a perowski

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JPS5058108A (OSRAM) * 1973-09-24 1975-05-20
US3997479A (en) * 1973-07-30 1976-12-14 Tdk Electronics Company, Limited Method of reducing the evaporation of Pb during the manufacture of barium titanate (Pb substituted) semiconducting ceramics
JPS57157502A (en) * 1981-03-24 1982-09-29 Murata Manufacturing Co Barium titanate series porcelain composition
US4447549A (en) * 1978-10-20 1984-05-08 Tdk Kabushiki Kaisha Non-linear dielectric element
US4824813A (en) * 1986-12-27 1989-04-25 Narumi China Corporation Dielectric ceramic composition
US4873610A (en) * 1986-03-20 1989-10-10 Canon Kabushiki Kaisha Dielectric articles and condensers using the same
US4898844A (en) * 1986-07-14 1990-02-06 Sprague Electric Company Process for manufacturing a ceramic body having multiple barium-titanate phases
US5818043A (en) * 1993-04-09 1998-10-06 Thomson-Csf Bolometric thermal detector
US6144286A (en) * 1998-04-24 2000-11-07 Dornier Gmbh PTCR-resistor
WO2002067341A1 (es) * 2001-02-21 2002-08-29 Consejo Superior De Investigaciones Científicas Procedimiento para aumentar la temperatura de curie en óxidos magnetoresistivos con estructura de doble perovskita
US20060033427A1 (en) * 2002-08-30 2006-02-16 Kenichi Nagayama Organic el element
US20100035749A1 (en) * 2008-08-08 2010-02-11 Ji-Won Choi Dielectric Thin Film Composition Showing Linear Dielectric Properties
US20110174803A1 (en) * 2008-08-07 2011-07-21 Epcos Ag Heating Device and Method for Manufacturing the Heating Device
US20110186711A1 (en) * 2008-08-07 2011-08-04 Epcos Ag Molded Object, Heating Device and Method for Producing a Molded Object
US20130244857A1 (en) * 2012-03-19 2013-09-19 Samhwa Capacitor Co., Ltd. Non-reducible low temperature sinterable dielectric ceramic composition for multi layer ceramic capacitor and manufacturing method thereof
CN117645481A (zh) * 2023-11-14 2024-03-05 中物院成都科学技术发展中心 一种高性能微波介质陶瓷及其冷烧结制备方法

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NL165020C (nl) * 1974-12-16 1981-02-16 Philips Nv Kleurentelevisie-ontvanger bevattende een ontmagneti- seerschakeling en samengesteld thermistorelement voor toepassing in een dergelijke schakeling.
DE2659672B2 (de) * 1976-12-30 1980-12-04 Siemens Ag, 1000 Berlin Und 8000 Muenchen Kondensatordielektrikum mit inneren Sperrschichten und Verfahren zu seiner Herstellung
US12387860B2 (en) 2020-05-29 2025-08-12 Tdk Electronics Ag Electrical component comprising an electrical resistor

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GB714965A (en) * 1951-05-23 1954-09-08 Philips Electrical Ind Ltd Improvements in or relating to semi-conductive material
US2981699A (en) * 1959-12-28 1961-04-25 Westinghouse Electric Corp Positive temperature coefficient thermistor materials
US3044968A (en) * 1958-05-13 1962-07-17 Westinghouse Electric Corp Positive temperature coefficient thermistor materials

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GB714965A (en) * 1951-05-23 1954-09-08 Philips Electrical Ind Ltd Improvements in or relating to semi-conductive material
US3044968A (en) * 1958-05-13 1962-07-17 Westinghouse Electric Corp Positive temperature coefficient thermistor materials
US2981699A (en) * 1959-12-28 1961-04-25 Westinghouse Electric Corp Positive temperature coefficient thermistor materials

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3997479A (en) * 1973-07-30 1976-12-14 Tdk Electronics Company, Limited Method of reducing the evaporation of Pb during the manufacture of barium titanate (Pb substituted) semiconducting ceramics
JPS5058108A (OSRAM) * 1973-09-24 1975-05-20
US4447549A (en) * 1978-10-20 1984-05-08 Tdk Kabushiki Kaisha Non-linear dielectric element
JPS57157502A (en) * 1981-03-24 1982-09-29 Murata Manufacturing Co Barium titanate series porcelain composition
US4873610A (en) * 1986-03-20 1989-10-10 Canon Kabushiki Kaisha Dielectric articles and condensers using the same
US4898844A (en) * 1986-07-14 1990-02-06 Sprague Electric Company Process for manufacturing a ceramic body having multiple barium-titanate phases
US4824813A (en) * 1986-12-27 1989-04-25 Narumi China Corporation Dielectric ceramic composition
US5818043A (en) * 1993-04-09 1998-10-06 Thomson-Csf Bolometric thermal detector
US6144286A (en) * 1998-04-24 2000-11-07 Dornier Gmbh PTCR-resistor
ES2189626A1 (es) * 2001-02-21 2003-07-01 Consejo Superior Investigacion Procedimiento para aumentar la temperatura de curie en oxidos magnetoresistivos con estructura de doble perovskita.
WO2002067341A1 (es) * 2001-02-21 2002-08-29 Consejo Superior De Investigaciones Científicas Procedimiento para aumentar la temperatura de curie en óxidos magnetoresistivos con estructura de doble perovskita
ES2189626B1 (es) * 2001-02-21 2005-03-16 Consejo Superior De Investigaciones Cientificas Procedimiento para aumentar la temperatura de curie en oxidos magnetoresistivos con estructura de doble perovskita.
US20060033427A1 (en) * 2002-08-30 2006-02-16 Kenichi Nagayama Organic el element
US20110174803A1 (en) * 2008-08-07 2011-07-21 Epcos Ag Heating Device and Method for Manufacturing the Heating Device
US20110186711A1 (en) * 2008-08-07 2011-08-04 Epcos Ag Molded Object, Heating Device and Method for Producing a Molded Object
US9321689B2 (en) * 2008-08-07 2016-04-26 Epcos Ag Molded object, heating device and method for producing a molded object
US9363851B2 (en) 2008-08-07 2016-06-07 Epcos Ag Heating device and method for manufacturing the heating device
US20100035749A1 (en) * 2008-08-08 2010-02-11 Ji-Won Choi Dielectric Thin Film Composition Showing Linear Dielectric Properties
US8030237B2 (en) * 2008-08-08 2011-10-04 Korea Institute Of Science And Technology Dielectric thin film composition showing linear dielectric properties
US20130244857A1 (en) * 2012-03-19 2013-09-19 Samhwa Capacitor Co., Ltd. Non-reducible low temperature sinterable dielectric ceramic composition for multi layer ceramic capacitor and manufacturing method thereof
US8916489B2 (en) * 2012-03-19 2014-12-23 Samhwa Capacitor Co., Ltd. Non-reducible low temperature sinterable dielectric ceramic composition for multi layer ceramic capacitor and manufacturing method thereof
CN117645481A (zh) * 2023-11-14 2024-03-05 中物院成都科学技术发展中心 一种高性能微波介质陶瓷及其冷烧结制备方法

Also Published As

Publication number Publication date
DE1490659B2 (de) 1972-01-13
AT259079B (de) 1967-12-27
GB1073940A (en) 1967-06-28
DE1490659A1 (de) 1969-09-04
NL6510074A (OSRAM) 1966-03-18
BE669782A (OSRAM) 1966-03-17
FR1448402A (fr) 1966-08-05
JPS5212398B1 (OSRAM) 1977-04-06

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